Frost preventer for freezer doors



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FROST PREVENTER FOR FREEZER DOORS JU/m V. Grubbsg Si.

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By WWW Filed June ll,

United States Patenti() FROST PREV ENTER FOR FREEZER DOORS John V. Grubbs, Sr., Mobile, Ala.

Application June 11, 1954, Serial No. 436,031

1 Claim. (Cl. 62-2) This invention relates to a frost preventer for freezer doors and more specifically provides an improved construction of low temperature compartments or enclosures in general of the type used for the refrigeration or storage of any material to be held for a period at temperatures below the freezing point of water, such as walk-in freezers, quick freezers, cold storage warehouses, deep freezers, or the like.

Such low temperature compartments are usually designed with a door opening with a pivotally mounted door thereon wherein the door includes a sealing gasket for engaging the surface of the outer wall of the compartment surrounding the door opening, thereby effectively sealing the low temperature compartment. When the door is opened, the differential in temperature between the interior of the compartment and the exterior of the compartment causes condensation to form on the contacting portions of the door and compartment wherein such condensation is frozen, thereby forming ice or frost which must be removed or the door will become frozen shut. Therefore, it is the primary object of the present invention to provide an improved construction wherein the formation of frost or ice between the door and compartment opening is prevented by the provision of a heating element peripherally embedded in the side edges of the opening, thereby heating the contacting surface between the door and door opening for preventing the formation of ice and drying any condensation that may be formed thereon,

Another object of this invention is to provide a frost prevention device for freezer doors or the like wherein a thermostat control is provided for regulating the temperature of the frost prevention device.

A still further object of this invention is to provide a frost preventer for freezer doors having a heat conducting cover plate for engagement by the sealing gasket of the freezer door wherein the heat of the frost preventer will be readily and quickly conducted to the freezer door for the prevention of the formation of ice between the door and the outer surface of the side edges of the door opening.

Still another important object of this invention is to provide a frost preventer for freezer doors that is simple in construction, easy to install on existing freezers or other low temperature compartments, efficient in operation, well adapted for its intended purposes and relatively inexpensive to manufacture, operate and maintain.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like reference numerals refer to like parts throughout, and in which:

Figure 1 is a side elevational view showing portions of the cover plate broken away with the frost preventer of the present invention installed adjacent the edges of a door opening in a walk-in type freezer; and

2,731,804 Patented Jan. 24, 1956 Figure 2 is a top plan sectional view taken substantially along section line 2 2 of Figure 1 with the door in closed position showing the relative position of the heating elements, conductive cover plate, closure door and the sealing gasket normally secured to the closure door.

Referring now specically to the drawings, it will be seen that the numeral 10 generally indicates the frost preventer for freezer doors or other low temperature compartments. The low temperature compartment includes an opening 12 having a framing or facing 14 extending around the peripheral sides thereof. A closure door 16 is pivotally mounted on the front facing 14 by hinge means 18 and the inner surface of the door 16 is provided with a peripheral sealing gasket 20 which engages the front surface of the framing members 14 thereby effectively sealing the compartment and opening 12 for retaining the low temperature air therein for retaining the material at a sub-freezing temperature.

Referring now specifically to Figure 2, it will be seen that a pair of parallel grooves 22 are positioned in the front surface of the framing or facing members 14 and a resistance type heating wire or other heating wires 24 are positioned in the grooves 22 and provided with suitable insulation 26. The wires 24 are inserted in the grooves 22 and are slightly smaller than the grooves 22 for adequate spacing by the wire 24 from the side walls of the groove. An elongated continuous cover plate 28 is positioned in covering relation to the grooves 22 and the cover plate 2S is secured to the framing 14 by screw fasteners 3) wherein the plate 28 is provided with countersunk openings for receiving the heads of the screw fasteners 30, thereby forming a smooth surface on the outer surface of the cover plate 28 for engagement by the sealing gasket 20 on the pivotal door 16. The plate 28 and screws 30 are constructed of a non-corrosive material, and the plate 28 is constructed of a highly conductive material wherein the heat of the electric wires 24 will be transmitted to the outer surface of the plate 28 wherein the plate 28 will be retained in a warm condition for preventing the formation of ice thereon.

Referring now to the upper portion of Figure l, it will be seen that an additional right angle groove 32 is provided between the grooves 22 and a heat bulb 34 is positioned therein and connected to an adjustable thermostat 36 by a suitable conduit 38. The thermostat 36 is provided with an adjustment knob 39 for setting the temperature of the frost prevention device 10. The thermostat is positioned in the electrical circuit and connected to the heating wires 24 and an electrical conductor 4() that is connected through a suitable electrical fitting 42 to an electrical supply wherein the amount of current transmitted to the heating wires 24 is controlled by the thermostat 36. Further, it will be seen that a suitable latch 44 is provided on the frame 14 for retaining the door 16 in closed position and the grooves 22 are interconnected at their remote ends by a transverse groove, and vertical grooves are provided in the facing 14 at the upper end thereof for permitting passage of the wires 24 therethrough.

ln operation, the electrical conductor 40 is connected to a suitable electrical supply and the operating knob 39 on the thermostat 36 is set at a desired reading wherein the heating wires 24 will transmit heat to the conductive plate 28 thereby raising the temperature of the conductive plate 28 and melting any ice or frost thereon and drying any condensation that may have accumulated on the surface thereof. This prevents the condensation from freezing between the sealing gasket 2l) and the plate 28, thereby freezing the door 16 in a closed position. The plate 28 may be constructed of any suitable non-corrosive material, such as stainless steel, galvanized metal, copper or other similar materials.

The screw fasteners 30 may also be constructed of noncorrosive materials such as brass or the like.

The device may be connected to any 110 or 220-volt power line, and the thermostatic temperature control will effectively control the device if set at a range from 40 to 60 F., and the power consumption of the frost preventer is approximately 225 watts in a normal installation. It will be readily seen that the frost preventer of the present invention prevents ice formation or frost formation on door facings regardless of the temperature within the compartment and regardless of the number of openings and closings of the door 16.

From the foregoing, the construction and operation of the device will be readily understood and further explanation is believed to be unnecessary. However, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling Within the scope of the appended claim.

What is claimed as new is as follows:

A frost prevention device for use in conjunction with an entrance opening in a Walk-in type low temperature compartment having a pivotally mounted closure door attached to the wall adjacent the opening, said door engaging a facing about three sides of the opening, said door having a peripheral gasket for engaging the outer surface of the facing, said facing having a pair of spaced parallel grooves in the outer surface therefor at each side edge of the opening, said facing having a transverse groove interconnecting the lower ends of said spaced grooves, said facing having a pair of spaced grooves in the front surface at the upper edge thereof and communicating with the parallel groove in the side edges, the upper of said grooves in the upper edge terminating centrally in vertically extending grooves disposed in the outer surface of the facing, a continuous heating element disposed in said grooves and having free ends connected to a thermostatic control device, said facing having an enlarged groove in the outer surface of the upper edge thereof for receiving a heat bulb for actuating said thermostatic control, and a flat cover plate of non-corrosive heat resistant material positioned over said grooves in the facing and forming a smooth seat for engagement by the gasket on the pivotal closure door, said cover plate conducting heat frorn the heating element for melting frost from the facing and closure door adjacent the opening.

References Cited in the le of this patent UNITED STATES PATENTS 1,710,405 Copeman Apr. 23, 1929 1,934,133 Lauderback Nov. 7, 1933 2,135,091 Newill NOV. 1, 1938 

